I had a bad experience at my club. A member had brought some guests over (which is allowed) and they were playing doubles. When their time was up, they would not move because my partner was delayed. I often practice serves by myself, and sometimes will do that for a long time without a partner, but evidently they thought that at least 2 people should be there or they would not give up the court. I had to call the office and have them thrown out. Before that, they started using tactics like starting a game in the middle of the dispute and then claiming they needed to finish it, etc. Luckily it never happened again.

If you have a reservation, it is your court. You paid for the time (either per hour or monthly dues). You can have a party with cake and ice cream if you want. This is different than a public court where you should not have a party with cake and ice cream and prevent someone else with equal rights to the court from playing tennis.